The Folic Acid and Zinc Supplementation Trial (FAZST) is a multi-center, double-blind, randomized placebo-controlled trial to assess the effects of follc acid and zinc supplementation among male partners of couples seeking assisted reproduction, on the trial's primary outcomes of semen quality and live birth. Male participants were randomized equally (1:1) either to active study supplement (combined 5 mg folic acid and 30 mg elemental zinc) or to matching placebo. The study intervention continued for 6 months from randomization, and male participants completed in-person study visits, which included blood, urine, and semen collection, at baseline, 2, 4, and 6 months. Female partners provided biospecimens at baseline and questionnaire data, and clinical outcomes were followed through chart abstraction. Trial recruitment was completed in December 2017, with a total of 2372 couples enrolled. The Impact of Diet, Exercise and Lifestyle (IDEAL) Fertility Study involves additional detailed follow-up on a subset of the female partners. Large biospecimen repository is available for analysis and offers a good platform for testing multiple hypotheses.